Certain heavy truck vehicles have a suspension system through which a rear of a truck cab is supported on an underlying chassis frame. The chassis frame is itself suspended by a suspension system between itself and road wheels on which the truck vehicle travels. The suspension system between the road wheels and the chassis frame is tuned to the load of the truck vehicle supported by the road wheels. In the absence of a suspension system between the rear of the cab and the chassis frame, the full effect of road disturbances transmitted to the chassis frame is also felt by the cab, and hence a cab occupant such as a driver of the truck vehicle, resulting in what might be considered a harsh ride characteristic for the particular truck vehicle.
A suspension system which suspends a cab rear on a chassis frame should provide both longitudinal (fore-aft) control and lateral (side-to-side) control of a cab while controlling vertical displacements between cab and chassis frame so as to alleviate harshness which would otherwise be present in the absence of a cab rear suspension system.